Back in the 1970s, it was thought that America’s growing appetite might exhaust Earth’s crust of just about every metal and mineral. But a surprising thing happened: even as our population kept growing, the intensity of use of the resources began to fall. For each new dollar in the economy, we used less copper and steel than we had used before — not just the relative but also the absolute use of nine basic commodities, flat or falling for about 20 years (Figure 8). By about 1990, Americans even began to use less plastic. America has started to dematerialize....The reversal in use of some of the materials so surprised me that Iddo Wernick, Paul Waggoner, and I undertook a detailed study of the use of 100 commodities in the United States from 1900 to 2010. One hundred commodities span just about everything from arsenic and asbestos to water and zinc. The soaring use of many resources up to about 1970 makes it easy to understand why Americans started Earth Day that year. Of the 100 commodities, we found that 36 have peaked in absolute use, including the villainous arsenic and asbestos (Figure 9). Another 53 commodities have peaked relative to the size of the economy, though not yet absolutely. Most of them now seem poised to fall (Figure 10). They include not only cropland and nitrogen, but even electricity and water. Only 11 of the 100 commodities are still growing in both relative and absolute use in America. These include chickens, the winning form of meat. Several others are elemental vitamins, like the gallium and indium used to dope or alloy other bulk materials and make them smarter.
Much dematerialization does not surprise us, when a single pocket-size smartphone replaces an alarm clock, flashlight, and various media players, along with all the CDs and DVDs.
But even Californians economizing on water in the midst of a drought may be surprised at what has happened to water withdrawals in America since 1970. Expert projections made in the 1970s showed rising water use to the year 2000, but what actually happened was a leveling off. While America added 80 million people –– the population of Turkey –– American water use stayed flat. In fact, US Geological Survey data through 2010 shows that water use has now declined below the level of 1970, while production of corn, for example, has tripled (Figure 11). More efficient water use in farming and power generation contribute the most to the reduction.